RESEARCH PROGRESS: 1. NMR Investigations of the Nucleic Acid Structure and Conformation. a. Conformational Analysis of Nucleic Acids using CArbon-13 NMR Heteronuclear Coupling Constants. b. PMR Studies on the Methyl (CH3), Methylene (CH2), and NH-N Hydrogen-Bonded Proton Resonances of Baker's Yeast tRNAphe, Its Fragments and tRNApheM. 2. Subtle Structural Requirements of the Interferon (IF) Induction Receptor to the rI.rC Duplex. 3. Investigation of the Structure and Properties of Oligonucleotide Phosphotriesters; a. Inhibition of in vitro tRNA Aminoacylation and Mammalian Cell Growth by an Oligonucleotide Phosphotriester. FUTURE PLANS: 1. A new deoxyribose decanucleotide self-complementary helix will be investigated in the coming year, in comparison to the ribosyl hexanucleotide helix. The conformation of the backbone of nucleic acids will be investigated. BIBLIOGRAPHIC REFERENCES: Kan, L.S., Paul O.P. Ts'o, F. von der Haar, M. Sprinzl, and F. Cramer. Proton Magnetic Resonance Studies on the Conformation of the Hexanucleotide, GmpApApYpAp psi p, and Related Fragments from the Anticodon Loop of Baker's yeast Phenylalanine Transfer Ribonucleic Acid. Biochemistry 14, 3278 (1975). Arya S.; W. Carter; J. Alderfer; P. Ts'o. Inhibition of Ribonucleic Acid-Directed Deoxyribonucleic Acid Polymerase of Murine Leukemia Virus by Polyribonucleotides and Their 2'-O-Methylated Derivatives. Molecular Pharmacology 11, 421 (1975).